President Trump issued an extraordinary challenge to his own party late Tuesday, threatening to shut down the government in a matter of weeks if Congress did not fund a wall on the southern border that was a signature promise of his campaign for the White House. Mr. Trump followed up on that threat on Wednesday by going after a key Republican senator on Twitter who has been skeptical of building a border wall between the United States and Mexico. Senator Jeff Flake of Arizona is also one of two Republican senators up for re-election next year in a swing state, and the president has put his finger on the scale toward a primary challenger, Kelli Ward. read more https://www.nytimes.com/2017/08/23/...mtrref=www.nytimes.com&mtrref=www.nytimes.com